In vitro fertilisation
|In vitro fertilisation|
Illustrated schematic of IVF with intracytoplasmic sperm injection.
In vitro fertilisation (IVF) is a process by which an egg is fertilised by sperm outside the body: in vitro ("in glass"). The process involves monitoring and stimulating a woman's ovulatory process, removing ovum or ova (egg or eggs) from the woman's ovaries and letting sperm fertilise them in a fluid medium in a laboratory. The fertilised egg (zygote) is cultured for 2–6 days in a growth medium and is then implanted in the same or another woman's uterus, with the intention of establishing a successful pregnancy.
IVF techniques can be employed in a variety of situations. It is a method of assisted reproductive technology for treatment of infertility. IVF techniques are also employed in gestational surrogacy, in which case the fertilised egg is implanted into a surrogate's uterus, and the resulting child is genetically unrelated to the surrogate. In some cases, donated eggs or sperms may be used. Some countries ban or otherwise regulate the availability of IVF treatment, giving raise to fertility tourism. Restrictions on availability of IVF include to single females, to lesbians and to surrogacy arrangements. Due to the costs of the procedure, IVF is generally attempted only after less expensive options have failed.
The first successful birth of a "test tube baby", Louise Brown, occurred in 1978. Louise Brown was born as a result of natural cycle IVF where no stimulation was made. Robert G. Edwards, the physiologist who developed the treatment, was awarded the Nobel Prize in Physiology or Medicine in 2010. With egg donation and IVF, women who are past their reproductive years or menopause can still become pregnant. Adriana Iliescu held the record as the oldest woman to give birth using IVF and donated egg, when she gave birth in 2004 at the age of 66, a record passed in 2006.
- 1 Terminology
- 2 Indications
- 3 Method
- 4 Success rates
- 5 Complications of the I.V.F procedure
- 6 Expansions
- 7 Leftover embryos or eggs
- 8 History
- 9 Ethics
- 10 Emotional involvement
- 11 Men and IVF
- 12 Availability and utilisation
- 13 Legal status
- 14 See also
- 15 References
- 16 Further reading
- 17 External links
The term in vitro, from the Latin meaning in glass, is used, because early biological experiments involving cultivation of tissues outside the living organism from which they came, were carried out in glass containers such as beakers, test tubes, or petri dishes.
Today, the term in vitro is used to refer to any biological procedure that is performed outside the organism in which it would normally have occurred, to distinguish it from an in vivo procedure, where the tissue remains inside the living organism within which it is normally found. A colloquial term for babies conceived as the result of IVF, "test tube babies", refers to the tube-shaped containers of glass or plastic resin, called test tubes, that are commonly used in chemistry labs and biology labs. However, in vitro fertilisation is usually performed in the shallower containers called Petri dishes. One IVF method, autologous endometrial coculture, is actually performed on organic material, but is still considered in vitro.
IVF may be used to overcome female infertility where it is due to problems with the fallopian tubes, making fertilisation in vivo difficult. It can also assist in male infertility, in those cases where there is a defect in sperm quality; in such cases intracytoplasmic sperm injection (ICSI) may be used, where a sperm cell is injected directly into the egg cell. This is used when sperm have difficulty penetrating the egg, and in these cases the partner's or a donor's sperm may be used. ICSI is also used when sperm numbers are very low. When indicated, the use of ICSI has been found to increase the success rates of IVF.
According to the British NICE guidelines, IVF treatment is appropriate in cases of unexplained infertility for women that have not conceived after 2 years of regular unprotected sexual intercourse. Other countries have different rules. (See infertility.)
IVF is also considered appropriate in cases where any of its expansions is of interest, that is, a procedure that is usually not necessary for the IVF procedure itself, but would be virtually impossible or technically difficult to perform without concomitantly performing methods of IVF. Such expansions include preimplantation genetic diagnosis (PGD) to rule out presence of genetic disorders, as well as egg donation or surrogacy where the woman providing the egg isn't the same who will carry the pregnancy to term. Further details in the Expansions-section below.
Theoretically, in vitro fertilisation could be performed by collecting the contents from a woman's fallopian tubes or uterus after natural ovulation, mixing it with sperm, and reinserting the fertilised ova into the uterus. However, without additional techniques, the chances of pregnancy would be extremely small. The additional techniques that are routinely used in IVF include ovarian hyperstimulation to generate multiple eggs or ultrasound-guided transvaginal oocyte retrieval directly from the ovaries; after which the ova and sperm are prepared, as well as culture and selection of resultant embryos before embryo transfer into a uterus.
Ovarian hyperstimulation is the stimulation to induce development of multiple follicles of the ovaries. It should start with response prediction by e.g. age, antral follicle count and level of anti-Müllerian hormone. The resulting prediction of e.g. poor or hyper-response to ovarian hyperstimulation determines the protocol and dosage for ovarian hyperstimulation.
Ovarian hyperstimulation also includes suppression of spontaneous ovulation, for which two main methods are available: Using a (usually longer) GnRH agonist protocol or a (usually shorter) GnRH antagonist protocol. In a standard long GnRH agonist protocol the day when hyperstimulation treatment is started and the expected day of later oocyte retrieval can be chosen to conform to personal choice, while in a GnRH antagonist protocol it must be adapted to the spontaneous onset of the previous menstruation. On the other hand, the GnRH antagonist protocol has a lower (or even eliminated) risk of ovarian hyperstimulation syndrome (OHSS), which is a life-threatening complication.
For the ovarian hyperstimulation in itself, injectable gonadotropins (usually FSH analogues) are generally used under close monitoring. Such monitoring frequently checks the estradiol level and, by means of gynecologic ultrasonography, follicular growth. Typically approximately 10 days of injections will be necessary.
Natural and mild IVF
There are several methods termed natural cycle IVF:
- IVF using no drugs for ovarian hyperstimulation, while drugs for ovulation suppression may still be used.
- IVF using ovarian hyperstimulation, including gonadotropins, but with a GnRH antagonist protocol so that the cycle initiates from natural mechanisms.
- Frozen embryo transfer; IVF using ovarian hyperstimulation, followed by embryo cryopreservation, followed by embryo transfer in a later, natural, cycle.
IVF using no drugs for ovarian hyperstimulation was the method for the conception of Louise Brown. This method can be successfully used when women want to avoid taking ovarian stimulating drugs with its associated side-effects. HFEA has estimated the live birth rate to be approximately 1.3% per IVF cycle using no hyperstimulation drugs for women aged between 40–42.
Mild IVF is a method where a small dose of ovarian stimulating drugs are used for a short duration during a woman’s natural cycle aimed at producing 2–7 eggs and creating healthy embryos. This method appears to be an advance in the field to reduce complications and side-effects for women and it is aimed at quality, and not quantity of eggs and embryos. One study comparing a mild treatment (mild ovarian stimulation with GnRH antagonist co-treatment combined with single embryo transfer) to a standard treatment (stimulation with a GnRH agonist long-protocol and transfer of two embryos) came to the result that the proportions of cumulative pregnancies that resulted in term live birth after 1 year were 43.4% with mild treatment and 44.7% with standard treatment. Mild IVF can be cheaper than conventional IVF and with a significantly reduced risk of multiple gestation and OHSS. }
Final maturation induction
When the ovarian follicles have reached a certain degree of development, induction of final oocyte maturation is performed, generally by an injection of human chorionic gonadotropin (hCG). Commonly, this is known as the "trigger shot." hCG acts as an analogue of luteinising hormone, and ovulation would occur between 38 and 40 hours after a single HCG injection, but the egg retrieval is performed at a time usually between 34 and 36 hours after hCG injection, that is, just prior to when the follicles would rupture. This avails for scheduling the egg retrieval procedure at a time where the eggs are fully mature. HCG injection confers a risk of ovarian hyperstimulation syndrome. Using a GnRH agonist instead of hCG eliminates the risk of ovarian hyperstimulation syndrome, but with a delivery rate of approximately 6% less than with hCG.
The eggs are retrieved from the patient using a transvaginal technique called transvaginal oocyte retrieval, involving an ultrasound-guided needle piercing the vaginal wall to reach the ovaries. Through this needle follicles can be aspirated, and the follicular fluid is passed to an embryologist to identify ova. It is common to remove between ten and thirty eggs. The retrieval procedure usually takes between 20 to 40 minutes, depending on the number of mature follicles, and is usually done under conscious sedation or general anaesthesia.
Egg and sperm preparation
In the laboratory, the identified eggs are stripped of surrounding cells and prepared for fertilisation. An oocyte selection may be performed prior to fertilisation to select eggs with optimal chances of successful pregnancy. In the meantime, semen is prepared for fertilisation by removing inactive cells and seminal fluid in a process called sperm washing. If semen is being provided by a sperm donor, it will usually have been prepared for treatment before being frozen and quarantined, and it will be thawed ready for use.
The sperm and the egg are incubated together at a ratio of about 75,000:1 in a culture media in order for the actual fertilisation to take place. A review in 2013 came to the result that a duration of this co-incubation of about 1 to 4 hours results in significantly higher pregnancy rates than 16 to 24 hours. In most cases, the egg will be fertilised during co-incubation and will show two pronuclei. In certain situations, such as low sperm count or motility, a single sperm may be injected directly into the egg using intracytoplasmic sperm injection (ICSI). The fertilised egg is passed to a special growth medium and left for about 48 hours until the egg consists of six to eight cells.
In gamete intrafallopian transfer, eggs are removed from the woman and placed in one of the fallopian tubes, along with the man's sperm. This allows fertilisation to take place inside the woman's body. Therefore, this variation is actually an in vivo fertilisation, not an in vitro fertilisation.
The main durations of embryo culture are until cleavage stage (day 2 to 4 after co-incubation) or the blastocyst stage (day 5 or 6 after co-incubation). Embryo culture until the blastocyst stage confers a significant increase in live birth rate per embryo transfer, but also confers a decreased number of embryos available for transfer and embryo cryopreservation, so the cumulative clinical pregnancy rates are increased with cleavage stage transfer. Transfer day 2 instead of day 3 after fertilization has no differences in live birth rate. There are significantly higher odds of preterm birth (odds ratio 1.3) and congenital anomalies (odds ratio 1.3) among births having from embryos cultured until the blastocyst stage compared with cleavage stage.
Laboratories have developed grading methods to judge oocyte and embryo quality. In order to optimise pregnancy rates, there is significant evidence that a morphological scoring system is the best strategy for the selection of embryos. Since 2009 where the first time-lapse microscopy system for IVF was approved for clinical use, morphokinetic scoring systems has shown to improve to pregnancy rates further.
Embryos are failed by the embryologist based on the amount of cells, evenness of growth and degree of fragmentation. The number to be transferred depends on the number available, the age of the woman and other health and diagnostic factors. In countries such as Canada, the UK, Australia and New Zealand, a maximum of two embryos are transferred except in unusual circumstances. In the UK and according to HFEA regulations, a woman over 40 may have up to three embryos transferred, whereas in the USA, younger women may have many embryos transferred based on individual fertility diagnosis. Most clinics and country regulatory bodies seek to minimise the risk of pregnancies carrying multiples, as it is not uncommon for more implantations to take than desired. The embryos judged to be the "best" are transferred to the patient's uterus through a thin, plastic catheter, which goes through her vagina and cervix. Several embryos may be passed into the uterus to improve chances of implantation and pregnancy.
Luteal support is the administration of medication, generally progesterone, progestins or GnRH agonists, to increase the success rate of implantation and early embryogenesis, thereby complementing and/or supporting the function of the corpus luteum. The live birth rate is significantly higher with progesterone for luteal support in IVF cycles with or without intracytoplasmic sperm injection (ICSI). Co-treatment with GnRH agonists further improves outcomes, by a live birth rate RD of +16% (95% confidence interval +10 to +22%).
IVF success rates are the percentage of all IVF procedures which result in a favorable outcome. Depending on the type of calculation used, this outcome may represent the number of confirmed pregnancies, called the pregnancy rate or number of live births, called the live birth rate.
Due to advancement in reproductive technology, the IVF success rates are substantially better today than they were just a few years ago.
Live birth rate
The live birth rate is the percentage of all IVF cycles that lead to a live birth. This rate does not include miscarriage or stillbirth and multiple-order births such as twins and triplets are counted as one pregnancy. A 2012 summary compiled by the Society for Reproductive Medicine which reports the average IVF success rates in the United States per age group using non-donor eggs compiled the following data:
|Live birth rate||40.7||31.3||22.2||11.8||3.9|
In 2006, Canadian clinics reported a live birth rate of 27%. Birth rates in younger patients were slightly higher, with a success rate of 35.3% for those 21 and younger, the youngest group evaluated. Success rates for older patients were also lower and decrease with age, with 37-year-olds at 27.4% and no live births for those older than 48, the oldest group evaluated. Some clinics exceeded these rates, but it is impossible to determine if that is due to superior technique or patient selection, because it is possible to artificially increase success rates by refusing to accept the most difficult patients or by steering them into oocyte donation cycles (which are compiled separately). Further, pregnancy rates can be increased by the placement of several embryos at the risk of increasing the chance for multiples.
The live birth rates using donor eggs are also given by the SART and include all age groups using either fresh or thawed eggs.
|Fresh donor egg embryos||Thawed donor egg embryos|
|Live birth rate||55.1||33.8|
Because not each IVF cycle that is started will lead to oocyte retrieval or embryo transfer, reports of live birth rates need to specify the denominator, namely IVF cycles started, IVF retrievals, or embryo transfers. The Society for Assisted Reproductive Technology (SART) summarised 2008-9 success rates for US clinics for fresh embryo cycles that did not involve donor eggs and gave live birth rates by the age of the prospective mother, with a peak at 41.3% per cycle started and 47.3% per embryo transfer for patients under 35 years of age.
IVF attempts in multiple cycles result in increased cumulative live birth rates. Depending on the demographic group, one study reported 45% to 53% for three attempts, and 51% to 71% to 80% for six attempts.
Pregnancy rate may be defined in various ways. In the United States, the pregnancy rate used by the Society for Assisted Reproductive Technology and the Centers for Disease Control (and appearing in the table in the Success Rates section above) are based on fetal heart motion observed in ultrasound examinations.
The 2009 summary compiled by the Society for Reproductive Medicine included the following data for the United States:
In 2006, Canadian clinics reported an average pregnancy rate of 35%. A French study estimated that 66% of patients starting IVF treatment finally succeed in having a child (40% during the IVF treatment at the center and 26% after IVF discontinuation). Achievement of having a child after IVF discontinuation was mainly due to adoption (46%) or spontaneous pregnancy (42%).
Success or failure factors
The main potential factors that influence pregnancy (and live birth) rates in IVF have been suggested to be maternal age, duration of infertility or subfertility, bFSH and number of oocytes, all reflecting ovarian function. Optimal woman’s age is 23–39 years at time of treatment.
In a 2005 Swedish study, 166 women were monitored starting one month before their IVF cycles, and the results showed no significant correlation between psychological stress and IVF outcome. The study concluded with the recommendation to clinics that it might be possible to reduce the stress experienced by IVF patients during the treatment procedure by informing them of those findings. While psychological stress experienced during a cycle might not influence an IVF outcome, it is possible that the experience of IVF can result in stress that leads to depression. The financial consequences alone of IVF can influence anxiety and become overwhelming. However, for many couples, the alternative is infertility, and the experience of infertility itself can also cause extreme stress and depression.
Biomarkers that affect the pregnancy chances of IVF include:
- Antral follicle count, with higher count giving higher success rates.
- Anti-Müllerian hormone levels, with higher levels indicating higher chances of pregnancy, as well as of live birth after IVF, even after adjusting for age.
- Factors of semen quality for the sperm provider.
- Level of DNA fragmentation as measured e.g. by Comet assay, advanced maternal age and semen quality.
- Women with ovary-specific FMR1 genotypes including het-norm/low have significantly decreased pregnancy chances in IVF.
- Progesterone elevation (PE) on the day of induction of final maturation is associated with lower pregnancy rates in IVF cycles in women undergoing ovarian stimulation using GnRH analogues and gonadotrophins. At this time, compared to a progesterone level below 0.8 ng/ml, a level between 0.8 and 1.1 ng/ml confers an odds ratio of pregnancy of approximately 0.8, and a level between 1.2 and 3.0 ng/ml confers an odds ratio of pregnancy of between 0.6 and 0.7. On the other hand, progesterone elevation does not seem to confer a decreased chance of pregnancy in frozen–thawed cycles and cycles with egg donation.
- Characteristics of cells from the cumulus oophorus and the membrana granulosa, which are easily aspirated during oocyte retrieval. These cells are closely associated with the oocyte and share the same microenvironment, and the rate of expression of certain genes in such cells are associated with higher or lower pregnancy rate.
- An endometrial thickness (EMT) of less than 7 mm decreases the pregnancy rate by an odds ratio of approximately 0.4 compared to an EMT of over 7 mm. However, such low thickness rarely occurs, and any routine use of this parameter is regarded as not justified.
Other determinants of outcome of IVF include:
- Tobacco smoking reduces the chances of IVF producing a live birth by 34% and increases the risk of an IVF pregnancy miscarrying by 30%.
- A body mass index (BMI) over 27 causes a 33% decrease in likelihood to have a live birth after the first cycle of IVF, compared to those with a BMI between 20 and 27. Also, pregnant women who are obese have higher rates of miscarriage, gestational diabetes, hypertension, thromboembolism and problems during delivery, as well as leading to an increased risk of fetal congenital abnormality. Ideal body mass index is 19–30.
- Salpingectomy or laparoscopic tubal occlusion before IVF treatment increases chances for women with hydrosalpinges
- Success with previous pregnancy and/or live birth increases chances
- Low alcohol/caffeine intake increases success rate
- The number of embryos transferred in the treatment cycle.
- Embryo quality
- Some studies also suggest the autoimmune disease may also play a role in decreasing IVF success rates by interfering with proper implantation of the embryo after transfer.
A 2013 review and metaanalysis of randomised controlled trials of acupuncture as an adjuvant therapy in IVF found no overall benefit, and concluded that an apparent benefit detected in a subset of published trials where the control group (those not using acupuncture) experienced a lower than average rate of pregnancy requires further study, due to the possibility of publication bias and other factors.
A Cochrane review came to the result that endometrial injury performed in the month prior to ovarian hyperstimulation appeared to increase both the live birth rate and clinical pregnancy rate in IVF compared with no endometrial injury. However, there was a lack of data reported on the rates of adverse outcomes such as miscarriage, multiple pregnancy, pain and/or bleeding.
For females, intake of antioxidants (such as N-acetyl-cysteine, melatonin, vitamin A, vitamin C, vitamin E, folic acid, myo-inositol, zinc or selenium have not been associated with a significantly increased live birth rate or clinical pregnancy rate in IVF according to Cochrane reviews. On the other hand, oral antioxidants given to the men in couples with male factor or unexplained subfertility resulted in significantly higher live birth rate in IVF.
Complications of the I.V.F procedure
The major complication of IVF is the risk of multiple births. This is directly related to the practice of transferring multiple embryos at embryo transfer. Multiple births are related to increased risk of pregnancy loss, obstetrical complications, prematurity, and neonatal morbidity with the potential for long term damage. Strict limits on the number of embryos that may be transferred have been enacted in some countries (e.g. Britain, Belgium) to reduce the risk of high-order multiples (triplets or more), but are not universally followed or accepted. Spontaneous splitting of embryos in the womb after transfer can occur, but this is rare and would lead to identical twins. A double blind, randomised study followed IVF pregnancies that resulted in 73 infants (33 boys and 40 girls) and reported that 8.7% of singleton infants and 54.2% of twins had a birth weight of < 2,500 grams (5.5 lb).
Recent evidence also suggest that singleton offspring after IVF is at higher risk for lower birth weight for unknown reasons.
Spread of infectious disease
By sperm washing, the risk that a chronic disease in the male providing the sperm would infect the female or offspring can be brought to negligible levels.
In males with hepatitis B, The Practice Committee of the American Society for Reproductive Medicine advises that sperm washing is not necessary in IVF to prevent transmission, unless the female partner has not been effectively vaccinated. In females with hepatitis B, the risk of vertical transmission during IVF is no different from the risk in spontaneous conception. However, there is not enough evidence to say that ICSI procedures are safe in females with hepatitis B in regard to vertical transmission to the offspring.
Regarding potential spread of HIV/AIDS, Japan's government prohibited the use of in vitro fertilisation procedures for couples in which both partners are infected with HIV. Despite the fact that the ethics committees previously allowed the Ogikubo, Tokyo Hospital, located in Tokyo, to use in vitro fertilisation for couples with HIV, the Ministry of Health, Labour and Welfare of Japan decided to block the practice. Hideji Hanabusa, the vice president of the Ogikubo Hospital, states that together with his colleagues, he managed to develop a method through which scientists are able to remove HIV from sperm.
Other risks to the egg provider/retriever
A risk of ovarian stimulation is the development of ovarian hyperstimulation syndrome, particularly if hCG is used for inducing final oocyte maturation. This results in swollen, painful ovaries. It occurs in 30% of patients. Mild cases can be treated with over the counter medications and cases can be resolved in the absence of pregnancy. In moderate cases, ovaries swell and fluid accumulated in the abdominal cavities and may have symptoms of heartburn, gas, nausea or loss of appetite. In severe cases patients have sudden excess abdominal pain, nausea, vomiting and will result in hospitalisation.
During egg retrieval, there’s a small chance of bleeding, infection, and damage to surrounding structures like bowel and bladder (transvaginal ultrasound aspiration) as well as difficulty in breathing, chest infection, allergic reactions to medication, or nerve damage (laproscopy).
Ectopic pregnancy may also occur if a fertilised egg develops outside the uterus, usually in the fallopian tubes and requires immediate destruction of the foetus.
IVF does not seem to be associated with an elevated risk of cervical cancer, nor with ovarian cancer or endometrial cancer when neutralising the confounder of infertility itself. Nor does it seem to impart any increased risk for breast cancer.
Regardless of pregnancy result, IVF treatment is usually stressful for patients. Neuroticism and the use of escapist coping strategies are associated with a higher degree of distress, while the presence social support has a relieving effect. A negative pregnancy test after IVF is associated with an increased risk for depression in women, but not with any increased risk of developing anxiety disorders. Pregnancy test results do not seem to be a risk factor for depression or anxiety among men.
A review in 2013 came to the result that infants resulting from IVF (with or without ICSI) have a relative risk of birth defects of 1.32 (95% confidence interval 1.24–1.42) compared to naturally conceived infants. In 2008, an analysis of the data of the National Birth Defects Study in the US found that certain birth defects were significantly more common in infants conceived through IVF, notably septal heart defects, cleft lip with or without cleft palate, esophageal atresia, and anorectal atresia; the mechanism of causality is unclear. However, in a population-wide cohort study of 308,974 births (with 6163 using assisted reproductive technology and following children from birth to age five) researchers found: "The increased risk of birth defects associated with IVF was no longer significant after adjustment for parental factors."  Parental factors included known independent risks for birth defects such as maternal age, smoking status, etc. Multivariate correction did not remove the significance of the association of birth defects and ICSI (corrected odds ratio 1.57), although the authors speculate that underlying male infertility factors (which would be associated with the use of ICSI) may contribute to this observation and were not able to correct for these confounders. The authors also found that a history of infertility elevated risk itself in the absence of any treatment (odds ratio 1.29), consistent with a Danish national registry study  and "...implicates patient factors in this increased risk." The authors of the Danish national registry study speculate: "...our results suggest that the reported increased prevalence of congenital malformations seen in singletons born after assisted reproductive technology is partly due to the underlying infertility or its determinants."
|hypertensive disorders of pregnancy||1.49||1.39–1.59|
|preterm rupture of membranes||1.16||1.07–1.26|
|induction of labour||1.18||1.10–1.28|
|small for gestational age||1.39||1.27–1.53|
Other risks to the offspring
If the underlying infertility is related to abnormalities in spermatogenesis, it is plausible, but too early to examine that male offspring is at higher risk for sperm abnormalities.
IVF does not seem to confer any risks regarding cognitive development, school performance, social functioning and behaviour. Also, IVF infants are known to be as securely attached to their parents as those who were naturally conceived, and IVF adolescents as are as well-adjusted as those who have been naturally conceived.
Limited long-term follow-up data suggest that IVF may be associated with an increased incidence of hypertension, impaired fasting glucose, increase in total body fat composition, advancement of bone age, subclinical thyroid disorder, early adulthood clinical depression and binge drinking in the offspring. It is not known, however, whether these potential associations are caused by the IVF procedure in itself, by adverse obstetric outcomes associated with IVF, by the genetic origin of the children or by yet unknown IVF-associated causes. Increases in embryo manipulation during IVF result in more deviant fetal growth curves, but birth weight does not seem to be a reliable marker of fetal stress.
IVF, including ICSI, is associated with an increased risk of imprinting disorders (including Prader-Willi syndrome and Angelman syndrome), with an odds ratio of 3.7 (95% confidence interval 1.4 to 9.7).
An IVF-associated incidence of cerebral palsy and neurodevelopmental delay are believed to be related to the confounders of prematurity and low birthweight. Similarly, an IVF-associated incidence of autism and attention-deficit disorder are believed to be related to confounders of maternal and obstetric factors.
Overall, IVF does not cause an increased risk of childhood cancer. Studies have shown a decrease in the risk of certain cancers and an increased risks of certain others including retinoblastoma hepatoblastoma and rhabdomyosarcoma.
There are various expansions or additional techniques that can be applied in IVF, which are usually not necessary for the IVF procedure itself, but would be virtually impossible or technically difficult to perform without concomitantly performing methods of IVF.
Preimplantation genetic screening or diagnosis (PGS or PGD)
Preimplantation genetic screening (PGS) or preimplantation genetic diagnosis (PGD) has been suggested to be able to be used in IVF to select an embryo that appears to have the greatest chances for successful pregnancy. However, a systematic review and meta-analysis of existing randomised controlled trials came to the result that there is no evidence of a beneficial effect of PGS as measured by live birth rate. On the contrary, for women of advanced maternal age, PGS significantly lowers the live birth rate. Technical drawbacks, such as the invasiveness of the biopsy, and non-representative samples because of mosaicism are the major underlying factors for inefficacy of PGS.
Still, as an expansion of IVF, patients who can benefit from PGS/PGD include:
- Couples who have a family history of inherited disease
- Couples who want to use gender selection to prevent a gender-linked disease
- Couples who already have a child with an incurable disease and need compatible cells from a second healthy child to cure the first, resulting in a "saviour sibling" that matches the sick child in HLA type.
PGS screens for numeral chromosomal abnormalities while PGD diagnosis the specific molecular defect of the inherited disease. In both PGS and PGD, individual cells from a pre-embryo, or preferably trophectoderm cells biopsied from a blastocyst, are analyzed during the IVF process. Before the transfer of a pre-embryo back to a woman's uterus, one or two cells are removed from the pre-embryos (8-cell stage), or preferably from a blastocyst. These cells are then evaluated for normality. Typically within one to two days, following completion of the evaluation, only the normal pre-embryos are transferred back to the woman's uterus. Alternatively, a blastocyst can be cryopreserved via vitrification and transferred at a later date to the uterus. In addition, PGS can significantly reduce the risk of multiple pregnancies because fewer embryos, ideally just one, are needed for implantation.
The Rand Consulting Group has estimated there to be 400,000 frozen embryos in the United States. The advantage is that patients who fail to conceive may become pregnant using such embryos without having to go through a full IVF cycle. Or, if pregnancy occurred, they could return later for another pregnancy. Spare oocytes or embryos resulting from fertility treatments may be used for oocyte donation or embryo donation to another woman or couple, and embryos may be created, frozen and stored specifically for transfer and donation by using donor eggs and sperm. Also, oocyte cryopreservation can be used for women who are likely to lose their ovarian reserve due to undergoing chemotherapy.
The outcome from using cryopreserved embryos has uniformly been positive with no increase in birth defects or development abnormalities.
- Intracytoplasmic sperm injection (ICSI) is where a single sperm is injected directly into an egg. Its main usage as an expansion of IVF is to overcome male infertility problems, although it may also be used where eggs cannot easily be penetrated by sperm, and occasionally in conjunction with sperm donation. It can be used in teratozoospermia, since once the egg is fertilised abnormal sperm morphology does not appear to influence blastocyst development or blastocyst morphology.
- Additional methods of embryo profiling. For example, methods are emerging in making comprehensive analyses of up to entire genomes, transcriptomes, proteomes and metabolomes which may be used to score embryos by comparing the patterns with ones that have previously been found among embryos in successful versus unsuccessful pregnancies.
- Assisted zona hatching (AZH) can be performed shortly before the embryo is transferred to the uterus. A small opening is made in the outer layer surrounding the egg in order to help the embryo hatch out and aid in the implantation process of the growing embryo.
- In egg donation and embryo donation, the resultant embryo after fertilisation is inserted in another woman than the one providing the eggs. These are resources for women with no eggs due to surgery, chemotherapy, or genetic causes; or with poor egg quality, previously unsuccessful IVF cycles or advanced maternal age. In the egg donor process, eggs are retrieved from a donor's ovaries, fertilised in the laboratory with the sperm from the recipient's partner, and the resulting healthy embryos are returned to the recipient's uterus.
- Embryo splitting can be used for twinning to increase the number of available embryos.
Leftover embryos or eggs
There may be leftover embryos or eggs from IVF procedures if the woman for whom they were originally created has successfully carried one or more pregnancies to term. With the woman's or couple's permission, these may be donated to help other women or couples as a means of third party reproduction.
In embryo donation, these extra embryos are given to other couples or women for transfer with the goal of producing a successful pregnancy. The resulting child is considered the child of the woman who carries it and gives birth, and not the child of the donor, the same as occurs with egg donation or sperm donation.
Typically, genetic parents donate the eggs to a fertility clinic or embryo bank where they are preserved by oocyte cryopreservation or embryo cryopreservation until a carrier is found for them. Typically the process of matching the embryo(s) with the prospective parents is conducted by the agency itself, at which time the clinic transfers ownership of the embryos to the prospective parents.
In the United States, women seeking to be an embryo recipient undergo infectious disease screening required by the U.S. Food and Drug Administration (FDA), and reproductive tests to determine the best placement location and cycle timing before the actual Embryo Transfer occurs. The amount of screening the embryo has already undergone is largely dependent on the genetic parents' own IVF clinic and process. The embryo recipient may elect to have her own embryologist conduct further testing.
Alternatives to donating unused embryos are destroying them (or having them implanted at a time where pregnancy is very unlikely), keeping them frozen indefinitely, or donating them for use in research (which results in their unviability). Individual moral views on disposing leftover embryos may depend on personal views on the beginning of human personhood and definition and/or value of potential future persons and on the value that is given to fundamental research questions. Some people believe donation of leftover embryos for research is a good alternative to discarding the embryos when patients receive proper, honest and clear information about the research project, the procedures and the scientific values.
In 1977, Steptoe and Edwards successfully carried out a pioneering conception which resulted in the birth of the world's first baby to be conceived by IVF, Louise Brown on 25 July 1978, in Oldham General Hospital, Greater Manchester, UK.
The second successful birth of a test tube baby occurred in India just 67 days after Louise Brown was born. The girl, named Durga conceived in vitro using the methods of Subhash Mukhopadhyay, a physician and researcher from Kolkata.
In a few cases, laboratory mix-ups (misidentified gametes, transfer of wrong embryos) have occurred, leading to legal action against the IVF provider and complex paternity suits. An example is the case of a woman in California who received the embryo of another couple and was notified of this mistake after the birth of her son. This has led to many authorities and individual clinics implementing procedures to minimise the risk of such mix-ups. The HFEA, for example, requires clinics to use a double witnessing system, the identity of specimens is checked by two people at each point at which specimens are transferred. Alternatively, technological solutions are gaining favour, to reduce the manpower cost of manual double witnessing, and to further reduce ths with uniquely numbered RFID tags which can be identified by readers connected to a computer. The computer tracks specimens throughout the process and alerts the embryologist if non-matching specimens are identified. Although the use of RFID tracking has expanded in the USA, it is still not widely adopted.
Preimplantation genetic diagnosis or screening
Another concern is that people will screen in or out for particular traits, using preimplantation genetic diagnosis or preimplantation genetic screening. For example, a deaf British couple, Tom and Paula Lichy, have petitioned to create a deaf baby using IVF. Some medical ethicists have been very critical of this approach. Jacob M. Appel wrote that "intentionally culling out blind or deaf embryos might prevent considerable future suffering, while a policy that allowed deaf or blind parents to select for such traits intentionally would be far more troublesome."
Profit desire of the industry
Many people do not oppose the IVF practice itself (i.e. the creating of a pregnancy through "artificial" ways) but are highly critical of the current state of the present day industry. Such individuals argue that the industry has now become a multi-billion industry, which is widely unregulated and prone to serious abuses in the desire of practitioners to obtain profit. For instance, in 2008, a California physician transferred 12 embryos to a woman who gave birth to octuplets (see Suleman octuplets). This has made international news, and had led to accusations that many doctors are willing to seriously endanger the health and even life of women in order to gain money. Robert Winston, professor of fertility studies at Imperial College London, had called the industry "corrupt" and "greedy" saying that "One of the major problems facing us in healthcare is that IVF has become a massive commercial industry," and that "What has happened, of course, is that money is corrupting this whole technology", and accused authorities of failing to protect couples from exploitation "The regulatory authority has done a consistently bad job. It's not prevented the exploitation of women, it's not put out very good information to couples, it's not limited the number of unscientific treatments people have access to". The IVF industry can thus be seen as an example of what social scientists are describing as an increasing trend towards a market-driven construction of health, medicine and the human body. The industry has been accused of making unscientific claims, and distorting facts relating to infertility, in particular through widely exaggerated claims about how common infertility is in society, in an attempt to get as many couples as possible and as soon as possible to try treatments (rather than trying to conceive naturally for a longer time). This risks removing infertility from its social context and reducing the experience to a simple biological malfunction, which not only can be treated through bio-medical procedures, but should be treated by them. Indeed, there are serious concerns about the overuse of treatments, for instance Dr. Sami David, a fertility specialist and one of the pioneers of the early days of the IVF treatments, has expressed disappointment over the current state of the industry, and said many procedures are unnecessary; he said: "It's being the first choice of treatment rather than the last choice. When it was first opening up in late 1970s, early 80s, it was meant to be the last resort. Now it's a first resort. I think that's an injustice to women. I also think it can harm women in the long run." IVF thus raises ethical issues concerning the abuse of bio-medical facts to ‘sell’ corrective procedures and treatments for conditions that deviate from a constructed ideal of the ‘healthy’ or ‘normal’ body i.e., fertile females and males with reproductive systems capable of co-producing offspring.
Pregnancy past menopause
Although menopause is a natural barrier to further conception, IVF has allowed women to be pregnant in their fifties and sixties. Women whose uterus has been appropriately prepared receive embryos that originated from an egg of an egg donor. Therefore, although these women do not have a genetic link with the child, they have an emotional link through pregnancy and childbirth. In many cases the genetic father of the child is the woman's partner. Even after menopause the uterus is fully capable of carrying out a pregnancy.
Same-sex couples, single and unmarried parents
A 2009 statement from the ASRM found no persuasive evidence that children are harmed or disadvantaged solely by being raised by single parents, unmarried parents, or homosexual parents. It did not support restricting access to assisted reproductive technologies on the basis of a prospective parent's marital status or sexual orientation.
Ethical concerns include reproductive rights, the welfare of offspring, nondiscrimination against unmarried individuals, homosexual, and professional autonomy.
A recent controversy in California focused on the question of whether physicians opposed to same-sex relationships should be required to perform IVF for a lesbian couple. Guadalupe T. Benitez, a lesbian medical assistant from San Diego, sued doctors Christine Brody and Douglas Fenton of the North Coast Women's Care Medical Group after Brody told her that she had "religious-based objections to treating her and homosexuals in general to help them conceive children by artificial insemination," and Fenton refused to authorise a refill of her prescription for the fertility drug Clomid on the same grounds. The California Medical Association had initially sided with Brody and Fenton, but the case, North Coast Women's Care Medical Group v. Superior Court, was decided unanimously by the California State Supreme Court in favor of Benitez on 19 August 2008.
Nadya Suleman came to international attention after having twelve embryos implanted, eight of which survived, resulting in eight newborns being added to her existing six-child family. The Medical Board of California sought to have fertility doctor Michael Kamrava, who treated Suleman, stripped of his license. State officials allege that performing Suleman's procedure is evidence of unreasonable judgment, substandard care, and a lack of concern for the eight children she would conceive and the six she was already struggling to raise. On 1 June 2011 the Medical Board issued a ruling that Kamrava's medical license be revoked effective 1 July 2011. 
Alana Stewart, who was conceived using donor sperm, began an online forum for donor children called AnonymousUS in 2010. The forum welcomes the viewpoints of anyone involved in the IVF process. Olivia Pratten, a donor-conceived Canadian, sued the province of British Columbia for access to records on her donor father's identity in 2008. "I’m not a treatment, I’m a person, and those records belong to me,” Pratten said. In May 2012, a court ruled in Pratten's favor, agreeing that the laws at the time discrimiated against donor children and making anonymous sperm and egg donation in British Columbia illegal.
In the U.K., Sweden, Norway, Germany, Italy, New Zealand, and some Australian states, donors are not paid and cannot be anonymous.
In 2012, a documentary called Anonymous Father's Day was released that focuses on donor-conceived children.
Discarding unwanted embryos
During the selection and transfer phases many embryos may be discarded in favour of others. This selection may be based on criteria such as handicaps, genetic disorders, or even simply sex. This is a question of ethics as no consensus exists in science, religion, and philosophy on when during the development of a human embryo, it should be recognized as a new person. For those who believe that this is at the moment of conception, IVF becomes a moral question when multiple eggs are fertilised, begin development, and only a few are chosen for implantation.
If IVF were to involve the fertilisation of only a single egg, or at least only an amount that will be implanted, then this would not be an issue. However, this has the chance of increasing costs dramatically as only a few eggs can be attempted at a time.
The Roman Catholic Church opposes all kinds of assisted reproductive technology and artificial contraception, claiming they separate the procreative goal of marital sex from the goal of uniting married couples. The Roman Catholic Church permits the use of a small number of reproductive technologies and contraceptive methods like Natural family planning, which involves charting ovulation times. The church allows other forms of reproductive technologies that allow conception to take place from normative sexual intercourse, such as a fertility lubricant. Pope Benedict XVI had publicly re-emphasised the Catholic Church's opposition to in vitro fertilisation, claiming it replaces love between a husband and wife. The Catechism of the Catholic Church claims that Natural law teaches that reproduction has an "inseparable connection" to sexual union of married couples. In addition, the church opposes IVF because it might cause disposal of embryos; in Catholicism, an embryo is viewed as an individual with a soul that must be treated as a person. The Catholic Church maintains that it is not objectively evil to be infertile, and advocates adoption as an option for such couples who still wish to have children.
- IVF of an egg from the wife with the sperm of her husband and the transfer of the fertilised egg back to the uterus of the wife is allowed, provided that the procedure is indicated for a medical reason and is carried out by an expert physician.
- Since marriage is a contract between the wife and husband during the span of their marriage, no third party should intrude into the marital functions of sex and procreation. This means that a third party donor is not acceptable, whether he or she is providing sperm, eggs, embryos, or a uterus. The use of a third party is tantamount to zina, or adultery.
Within the Orthodox Jewish community the concept is debated as there is little precedent in traditional Jewish legal textual sources. Regarding laws of sexuality, religious challenges include masturbation (which may be regarded as “seed wasting”), laws related to sexual activity and menstruation (niddah) and the specific laws regarding intercourse. An additional major issue is that of establishing paternity and lineage. For a baby conceived naturally, the father’s identity is determined by a legal presumption (chazakah) of legitimacy: rov bi'ot achar ha'baal - a woman's sexual relations are assumed to be with her husband. Regarding an IVF child, this assumption does not exist and as such Rabbi Eliezer Waldenberg (among others) requires an outside supervisor to positively identify the father. Reform Judaism has generally approved in vitro fertilisation.
Society and culture
Many people of sub-Saharan Africa choose to foster their children to infertile women. IVF enables these infertile women to have their own children, which imposes new ideals to a culture in which fostering children is seen as both natural and culturally important. Many infertile women are able to earn more respect in their society by taking care of the children of other mothers, and this may be lost if they choose to use IVF instead. As IVF is seen as unnatural, it may even hinder their societal position as opposed to making them equal with fertile women. It is also economically advantageous for infertile women to raise foster children as it gives these children greater ability to access resources that are important for their development and also aids the development of their society at large. If IVF becomes more popular without the birth rate decreasing, there could be more large family homes with fewer options to send their newborn children. This could result in an increase of orphaned children and/or a decrease in resources for the children of large families. This would ultimately stifle the children's and the community's growth.
Studies have indicated that IVF mothers show greater emotional involvement with their child, and they enjoy motherhood more than mothers by natural conception. Similarly, studies have indicated that IVF fathers express more warmth and emotional involvement than fathers by adoption and natural conception and enjoy fatherhood more. Some IVF parents become overly involved with their children.
Men and IVF
Research has shown that men largely view themselves as ‘passive’ contributors since they have ‘less physical involvement' in IVF treatment. Despite this, many men feel distressed after seeing the toll of hormonal injections and ongoing physical intervention on their partner. Fertility was found to be a significant factor in a man’s perception of his masculinity, driving many to keep the treatment a secret. In cases where the men did share that he and his partner were undergoing IVF, they reported to have been teased, mainly by other men, although some viewed this as an affirmation of support and friendship. For others, this led to feeling socially isolated. In comparison with women, men showed less deterioration in mental health in the years following a failed treatment. However many men did feel guilt, disappointment and inadequacy, stating that they were simply trying to provide an ‘emotional rock’ for their partners.
Availability and utilisation
In the USA, overall availability of IVF in 2005 was 2.5 IVF physicians per 100,000 population, and utilisation was 236 IVF cycles per 100,000. Utilisation highly increases with availability and IVF insurance coverage, and to a significant extent also with percentage of single persons and median income. In the USA 126 procedures are performed per million people per year. In the USA an average cycle, from egg retrieval to embryo implantation, costs $12,400, and insurance companies that do cover treatment, even partially, usually cap the number of cycles they pay for.
The cost of IVF rather reflects the costliness of the underlying healthcare system than the regulatory or funding environment, and ranges, on average for a standard IVF cycle and in 2006 United States dollars, between $12,500 in the United States to $4,000 in Japan. In Ireland, IVF costs around €4,000, with fertility drugs, if required, costing up to €3,000. The cost per live birth is highest in the United States ($41,000) and United Kingdom ($40,000) and lowest in Scandinavia and Japan (both around $24,500).
Many fertility clinics in the United States limit the upper age at which women are eligible for IVF to 50 or 55 years. These cut-offs make it difficult for women older than fifty-five to utilise the procedure.
Israel has the highest rate of IVF in the world, with 1657 procedures performed per million people per year. The second highest rate is in Iceland, with 899 procedures per million people per year. Israel provides unlimited free in vitro procedures for its citizens for up to two children per woman under 45 years of age. In other countries the coverage of such procedures is limited if it exists at all. The Israeli Health Ministry says it spends roughly $3450 per procedure.
These high costs keep IVF out of reach for many developing countries, but research by the Genk Institute for Fertility Technology, in Belgium, claim to have found a much lower cost methodology (about 90% reduction) with similar efficacy, which may be suitable for some fertility treatment.
Government agencies in China passed bans on the use of IVF in 2003 by unmarried women or by couples with certain infectious diseases.
Sunni Muslim nations generally allow IVF between married couples when conducted with their own respective sperm and eggs, but not with donor eggs from other couples. But Iran, which is Shi'a Muslim, has a more complex scheme. Iran bans sperm donation but allows donation of both fertilised and unfertilised eggs. Fertilised eggs are donated from married couples to other married couples, while unfertilised eggs are donated in the context of mut'ah or temporary marriage to the father.
Costa Rica has a complete ban on IVF technology, it having been ruled unconstitutional by the nation's Supreme Court because it "violated life." Costa Rica is the only country in the western hemisphere that forbids IVF. A law project sent reluctantly by the government of President Laura Chinchilla was rejected by parliament. President Chinchilla has not publicly stated her position on the question of IVF. However, given the massive influence of the Catholic Church in her government any change in the status quo seems very unlikely. In spite of Costa Rican government and strong religious opposition, the IVF ban has been struck down by the Inter-American Court of Human Rights in a decision of 20 December 2012. The court said that a long-standing Costa Rican guarantee of protection for every human embryo violated the reproductive freedom of infertile couples because it prohibited them from using IVF, which often involves the disposal of embryos not implanted in a patient’s uterus.
All major restrictions on single but infertile women using IVF were lifted in Australia in 2002 after a final appeal to the Australian High Court was rejected on procedural grounds in the Leesa Meldrum case. A Victorian federal court had ruled in 2000 that the existing ban on all single women and lesbians using IVF constituted sex discrimination. Victoria's government announced changes to its IVF law in 2007 eliminating remaining restrictions on fertile single women and lesbians, leaving South Australia as the only state maintaining them.
Federal regulations in the United States include screening requirements and restrictions on donations, but generally do not affect sexually intimate partners. However, doctors may be required to provide treatments due to nondiscrimination laws, as for example in California. The US state of Tennessee proposed a bill in 2009 that would have defined donor IVF as adoption. During the same session another bill proposed barring adoption from any unmarried and cohabitating couple, and activist groups stated that passing the first bill would effectively stop unmarried people from using IVF. Neither of these bills passed.
- Assisted reproduction
- Commercial surrogacy
- Evans v. the United Kingdom, a key case at the European Court of Human Rights
- Sperm bank
- Sperm donation
- Elizabeth Jordan Carr
- Louise Brown
- Fertility: assessment and treatment for people with fertility problems. NICE clinical guideline CG156 – Issued: February 2013
- La Marca A, Sunkara SK (2014). "Individualization of controlled ovarian stimulation in IVF using ovarian reserve markers: from theory to practice". Hum. Reprod. Update 20 (1): 124–40. doi:10.1093/humupd/dmt037. PMID 24077980.
- Allersma T, Farquhar C, Cantineau AE (2013). "Natural cycle in vitro fertilisation (IVF) for subfertile couples". Cochrane Database Syst Rev 8: CD010550. doi:10.1002/14651858.CD010550.pub2. PMID 23990351.
- Evans, J.; Hannan, N. J.; Edgell, T. A.; Vollenhoven, B. J.; Lutjen, P. J.; Osianlis, T.; Salamonsen, L. A.; Rombauts, L. J. F. (2014). "Fresh versus frozen embryo transfer: backing clinical decisions with scientific and clinical evidence". Human Reproduction Update 20 (6): 808–821. doi:10.1093/humupd/dmu027. ISSN 1355-4786.
- Natural cycle IVF at the Human Fertilisation and Embryology Authority homepage.
- Nargund G (2009). "Natural/mild assisted reproductive technologies: Reducing cost and increasing safety". Women's Health 5 (4): 359–360. doi:10.2217/whe.09.32. PMID 19586428.
- Heijnen EM, Eijkemans MJ, De Klerk C, Polinder S, Beckers NG, Klinkert ER, Broekmans FJ, Passchier J, Te Velde ER, Macklon NS, Fauser BC (2007). "A mild treatment strategy for in-vitro fertilisation: a randomised non-inferiority trial". Lancet 369 (9563): 743–9. doi:10.1016/S0140-6736(07)60360-2. PMID 17336650.
- Fauser BC, Nargund G, Andersen AN, Norman R, Tarlatzis B, Boivin J, Ledger W (2010). "Mild ovarian stimulation for IVF: 10 years later". Human Reproduction 25 (11): 2678–2684. doi:10.1093/humrep/deq247. PMID 20858698.
- "IVF Treatment Step Four: Final Oocyte". Infertility.about.com. Retrieved 22 May 2012.
- HCG Injection After Ovulation Induction With Clomiphene Citrate at Medscape. By Peter Kovacs. Posted: 23 April 2004
- Humaidan P, Kol S, Papanikolaou EG (2011). "GnRH agonist for triggering of final oocyte maturation: time for a change of practice?". Hum. Reprod. Update 17 (4): 510–524. doi:10.1093/humupd/dmr008. PMID 21450755.
- Zhang XD, Liu JX, Liu WW, Gao Y, Han W, Xiong S, Wu LH, Huang GN (2013). "Time of insemination culture and outcomes of in vitro fertilization: A systematic review and meta-analysis". Human Reproduction Update 19 (6): 685–695. doi:10.1093/humupd/dmt036. PMID 23912477.
- Dar S, Lazer T, Shah PS, Librach CL (2014). "Neonatal outcomes among singleton births after blastocyst versus cleavage stage embryo transfer: a systematic review and meta-analysis". Hum. Reprod. Update 20 (3): 439–48. doi:10.1093/humupd/dmu001. PMID 24480786.
- Farquhar C, Rishworth JR, Brown J, Nelen WL, Marjoribanks J (2013). "Assisted reproductive technology: an overview of Cochrane Reviews". Cochrane Database Syst Rev 8: CD010537. doi:10.1002/14651858.CD010537.pub2. PMID 23970457.
- Rebmann V, Switala M, Eue I, Grosse-Wilde H (May 2010). "Soluble HLA-G is an independent factor for the prediction of pregnancy outcome after ART: a German multi-centre study". Hum Reprod 25 (7): 1691–8. doi:10.1093/humrep/deq120. PMID 20488801.
- "Unisense FertiliTech A/S Receives CE Mark of Approval for EmbryoScope(TM) Embryo Monitoring System".
- Meseguer M, Rubio I, Cruz M, Basile N, Marcos J, Requena A (2012). "Embryo incubation and selection in a time-lapse monitoring system improves pregnancy outcome compared with a standard incubator: A retrospective cohort study". Fertility and Sterility 98 (6): 1481–1489.e10. doi:10.1016/j.fertnstert.2012.08.016. PMID 22975113.
- van der Linden M, Buckingham K, Farquhar C, Kremer JA, Metwally M (2011). "Luteal phase support for assisted reproduction cycles". Cochrane Database Syst Rev (10): CD009154. doi:10.1002/14651858.CD009154.pub2. PMID 21975790.
- Kyrou D, Kolibianakis EM, Fatemi HM, Tarlatzi TB, Devroey P, Tarlatzis BC (2011). "Increased live birth rates with GnRH agonist addition for luteal support in ICSI/IVF cycles: A systematic review and meta-analysis". Human Reproduction Update 17 (6): 734–740. doi:10.1093/humupd/dmr029. PMID 21733980.
- "2012 Clinic Summary Report". Society for Reproductive Medicine. Retrieved 2014-11-06.
- Branswell, Helen (15 December 2008) Success rate climbs for in vitro fertilization. The Canadian Press.
- "2006 Assisted Reproductive Technology (ART) Report: Section 2". Centers for Disease Control and Prevention. Retrieved 25 March 2009.
- "2009 Clinic Summary Report". Society for Reproductive Medicine. Retrieved 14 July 2011.
- Study: Sixth Time May Be Charm For In Vitro by Patti Neighmond. Day to Day, National Public Radio. 21 January 2009.
- de La Rochebrochard E, Quelen C, Peikrishvili R, Guibert J, Bouyer J (2008). "Long-term outcome of parenthood project during in vitro fertilization and after discontinuation of unsuccessful in vitro fertilization". Fertil. Steril. 92 (1): 149–56. doi:10.1016/j.fertnstert.2008.05.067. PMID 18706550.
- van Loendersloot LL, van Wely M, Limpens J, Bossuyt PM, Repping S, van der Veen F (2010). "Predictive factors in in vitro fertilization (IVF): a systematic review and meta-analysis". Human Reproduction Update 16 (6): 577–589. doi:10.1093/humupd/dmq015. PMID 20581128.
- Nice.org Fertility: Assessment and Treatment for People with Fertility Problems. London: RCOG Press. 2004. ISBN 1-900364-97-2.
- Schmidt L, Holstein BE, Christensen U, Boivin J (November 2005). "Communication and coping as predictors of fertility problem stress: cohort study of 816 participants who did not achieve a delivery after 12 months of fertility treatment". Hum. Reprod. 20 (11): 3248–56. doi:10.1093/humrep/dei193. PMID 16006458.
- Zhao, Jing; Zhang, Qiong; Li, Yanping (2012). "The effect of endometrial thickness and pattern measured by ultrasonography on pregnancy outcomes during IVF-ET cycles". Reproductive Biology and Endocrinology 10 (1): 100. doi:10.1186/1477-7827-10-100. ISSN 1477-7827.
- Broer SL, van Disseldorp J, Broeze KA, Dolleman M, Opmeer BC, Bossuyt P, Eijkemans MJ, Mol BW, Broekmans FJ (2012). "Added value of ovarian reserve testing on patient characteristics in the prediction of ovarian response and ongoing pregnancy: An individual patient data approach". Human Reproduction Update 19 (1): 26–36. doi:10.1093/humupd/dms041. PMID 23188168.
- Iliodromiti, S.; Kelsey, T. W.; Wu, O.; Anderson, R. A.; Nelson, S. M. (2014). "The predictive accuracy of anti-Mullerian hormone for live birth after assisted conception: a systematic review and meta-analysis of the literature". Human Reproduction Update 20 (4): 560–570. doi:10.1093/humupd/dmu003. ISSN 1355-4786.
- Simon L, Brunborg G, Stevenson M, Lutton D, McManus J, Lewis SE (May 2010). "Clinical significance of sperm DNA damage in assisted reproduction outcome". Hum Reprod 25 (7): 1594–608. doi:10.1093/humrep/deq103. PMID 20447937.
- Gleicher N, Weghofer A, Lee IH, Barad DH (2010). "FMR1 Genotype with Autoimmunity-Associated Polycystic Ovary-Like Phenotype and Decreased Pregnancy Chance". PLoS ONE 5 (12): e15303. doi:10.1371/journal.pone.0015303. PMC 3002956. PMID 21179569.
- Venetis CA, Kolibianakis EM, Bosdou JK, Tarlatzis BC (2013). "Progesterone elevation and probability of pregnancy after IVF: A systematic review and meta-analysis of over 60 000 cycles". Human Reproduction Update 19 (5): 433–457. doi:10.1093/humupd/dmt014. PMID 23827986.
- Fragouli E, Lalioti MD, Wells D (2013). "The transcriptome of follicular cells: Biological insights and clinical implications for the treatment of infertility". Human Reproduction Update 20 (1): 1–11. doi:10.1093/humupd/dmt044. PMC 3845680. PMID 24082041.
- Kasius, A.; Smit, J. G.; Torrance, H. L.; Eijkemans, M. J. C.; Mol, B. W.; Opmeer, B. C.; Broekmans, F. J. M. (2014). "Endometrial thickness and pregnancy rates after IVF: a systematic review and meta-analysis". Human Reproduction Update 20 (4): 530–541. doi:10.1093/humupd/dmu011. ISSN 1355-4786.
- Regulated fertility services: a commissioning aid – June 2009. Department of Health UK. 18 June 2009
- Factors affecting IVF success – February 2011, from IVF-infertility.com
- Siristatidis CS, Dodd SR, Drakeley AJ (2011). "Aspirin for in vitro fertilisation". Cochrane Database Syst Rev (8): CD004832. doi:10.1002/14651858.CD004832.pub3. PMID 21833951.
- Groeneveld E, Broeze KA, Lambers MJ, Haapsamo M, Dirckx K, Schoot BC, Salle B, Duvan CI, Schats R, Mol BW, Hompes PG (2011). "Is aspirin effective in women undergoing in vitro fertilization (IVF)? Results from an individual patient data meta-analysis (IPD MA)". Human Reproduction Update 17 (4): 501–509. doi:10.1093/humupd/dmr007. PMID 21422062.
- Manheimer E, van der Windt D, Cheng K, Stafford K, Liu J, Tierney J, Lao L, Berman BM, Langenberg P, Bouter LM (2013). "The effects of acupuncture on rates of clinical pregnancy among women undergoing in vitro fertilization: A systematic review and meta-analysis". Human Reproduction Update 19 (6): 696–713. doi:10.1093/humupd/dmt026. PMC 3796945. PMID 23814102.
- Olivennes F, Mannaerts B, Struijs M, Bonduelle M, Devroey P (2001). "Perinatal outcome of pregnancy after GnRH antagonist (ganirelix) treatment during ovarian stimulation for conventional IVF or ICSI: a preliminary report". Hum. Reprod. 16 (8): 1588–91. doi:10.1093/humrep/16.8.1588. PMID 11473947.
- "Hepatitis and reproduction". Fertility and Sterility 90 (5): S226–S235. 2008. doi:10.1016/j.fertnstert.2008.08.040. PMID 19007636.
- Lutgens SP, Nelissen EC, van Loo IH, Koek GH, Derhaag JG, Dunselman GA (2009). "To do or not to do: IVF and ICSI in chronic hepatitis B virus carriers". Human Reproduction 24 (11): 2676–2678. doi:10.1093/humrep/dep258. PMID 19625309.
- "Japan Bans in Vitro Fertilisation for HIV Couples". Infoniac.com. 21 July 2008.
- Siristatidis C, Sergentanis TN, Kanavidis P, Trivella M, Sotiraki M, Mavromatis I, Psaltopoulou T, Skalkidou A, Petridou ET (2012). "Controlled ovarian hyperstimulation for IVF: Impact on ovarian, endometrial and cervical cancer--a systematic review and meta-analysis". Human Reproduction Update 19 (2): 105–123. doi:10.1093/humupd/dms051. PMID 23255514.
- Sergentanis TN, Diamantaras AA, Perlepe C, Kanavidis P, Skalkidou A, Petridou ET (2013). "IVF and breast cancer: A systematic review and meta-analysis". Human Reproduction Update 20 (1): 106–123. doi:10.1093/humupd/dmt034. PMID 23884897.
- Rockliff, H. E.; Lightman, S. L.; Rhidian, E.; Buchanan, H.; Gordon, U.; Vedhara, K. (2014). "A systematic review of psychosocial factors associated with emotional adjustment in in vitro fertilization patients". Human Reproduction Update 20 (4): 594–613. doi:10.1093/humupd/dmu010. ISSN 1355-4786.
- Volgsten H, Skoog Svanberg A, Ekselius L, Lundkvist O, Sundström Poromaa I (March 2010). "Risk factors for psychiatric disorders in infertile women and men undergoing in vitro fertilization treatment". Fertil Steril 93 (4): 1088–1096. doi:10.1016/j.fertnstert.2008.11.008. PMID 19118826.
- Hansen M, Kurinczuk JJ, Milne E, de Klerk N, Bower C (2013). "Assisted reproductive technology and birth defects: a systematic review and meta-analysis". Hum. Reprod. Update 19 (4): 330–53. doi:10.1093/humupd/dmt006. PMID 23449641.
- Reefhuis J, Honein MA, Schieve LA, Correa A, Hobbs CA, Rasmussen SA (February 2009). "Assisted reproductive technology and major structural birth defects in the United States". Hum. Reprod. 24 (2): 360–6. doi:10.1093/humrep/den387. PMID 19010807.
- Davies MJ, Moore VM, Willson KJ, Van Essen P, Priest K, Scott H, Haan EA, Chan A (2012). "Reproductive technologies and the risk of birth defects". New England Journal of Medicine 366 (19): 1803–13. doi:10.1056/NEJMoa1008095. PMID 22559061.
- Zhu JL, Basso O, Obel C, Bille C, Olsen J (2006). "Infertility, infertility treatment, and congenital malformations: Danish national birth cohort". British Medical Journal 333 (7570): 679. doi:10.1136/bmj.38919.495718.AE. PMC 1584372. PMID 16893903.
- Pandey S, Shetty A, Hamilton M, Bhattacharya S, Maheshwari A (2012). "Obstetric and perinatal outcomes in singleton pregnancies resulting from IVF/ICSI: A systematic review and meta-analysis". Human Reproduction Update 18 (5): 485–503. doi:10.1093/humupd/dms018. PMID 22611174.
- Hart R, Norman RJ (2013). "The longer-term health outcomes for children born as a result of IVF treatment. Part II-Mental health and development outcomes". Human Reproduction Update 19 (3): 244–250. doi:10.1093/humupd/dmt002. PMID 23449643.
- Berk, Laura E. Infants, Children, and Adolescents, 7th Edition. Pearson Learning Solutions, 12/2010. VitalBook file., p. 67
- Hart R, Norman RJ (2013). "The longer-term health outcomes for children born as a result of IVF treatment: Part I-General health outcomes". Human Reproduction Update 19 (3): 232–243. doi:10.1093/humupd/dms062. PMID 23449642.
- Bloise, E.; Feuer, S. K.; Rinaudo, P. F. (2014). "Comparative intrauterine development and placental function of ART concepti: implications for human reproductive medicine and animal breeding". Human Reproduction Update 20 (6): 822–839. doi:10.1093/humupd/dmu032. ISSN 1355-4786.
- Lazaraviciute, G.; Kauser, M.; Bhattacharya, S.; Haggarty, P.; Bhattacharya, S. (2014). "A systematic review and meta-analysis of DNA methylation levels and imprinting disorders in children conceived by IVF/ICSI compared with children conceived spontaneously". Human Reproduction Update 20 (6): 840–852. doi:10.1093/humupd/dmu033. ISSN 1355-4786.
- Williams CL, Bunch KJ, Stiller CA, Murphy MF, Botting BJ, Wallace WH, Davies M, Sutcliffe AG (2013). "Cancer Risk among Children Born after Assisted Conception". New England Journal of Medicine 369 (19): 1819–1827. doi:10.1056/NEJMoa1301675. PMID 24195549.
- Marees T, Dommering CJ, Imhof SM, Kors WA, Ringens PJ, van Leeuwen FE, Moll AC (2009). "Incidence of retinoblastoma in Dutch children conceived by IVF: an expanded study". Hum. Reprod. 24 (12): 3220–4. doi:10.1093/humrep/dep335. PMID 19783550.
- Mastenbroek S, Twisk M, van der Veen F, Repping S (2011). "Preimplantation genetic screening: A systematic review and meta-analysis of RCTs". Human Reproduction Update 17 (4): 454–466. doi:10.1093/humupd/dmr003. PMID 21531751.
- Britten, Nick (2011) Saviour Sibling Cures Sick Older Brother The Daily Telegraph, Health News, 7 May 2011. Retrieved 8 May 2011
- Mundy, Liza (July–August 2006). "Souls On Ice: America's Embryo Glut and the Wasted Promise of Stem Cell Research". Motherjones.com.
- Porcu E, Fabbri R, Damiano G, Fratto R, Giunchi S, Venturoli S (2004). "Oocyte cryopreservation in oncological patients". Eur J Obstet Gynecol Reprod Biol. 113 Suppl 1: S14–6. doi:10.1016/j.ejogrb.2003.11.004. PMID 15041124.
- "Genetics & IVF Institute". Givf.com. Archived from the original on 27 July 2009. Retrieved 27 July 2009.
- French DB, Sabanegh ES, Goldfarb J, Desai N (March 2010). "Does severe teratozoospermia affect blastocyst formation, live birth rate, and other clinical outcome parameters in ICSI cycles?". Fertil Steril 93 (4): 1097–1103. doi:10.1016/j.fertnstert.2008.10.051. PMID 19200957.
- Fauser BC, Diedrich K, Bouchard P, Domínguez F, Matzuk M, Franks S, Hamamah S, Simón C, Devroey P, Ezcurra D, Howles CM (2011). "Contemporary genetic technologies and female reproduction". Human Reproduction Update 17 (6): 829–847. doi:10.1093/humupd/dmr033. PMC 3191938. PMID 21896560.
- Illmensee K, Levanduski M, Vidali A, Husami N, Goudas VT (February 2009). "Human embryo twinning with applications in reproductive medicine". Fertil. Steril. 93 (2): 423–7. doi:10.1016/j.fertnstert.2008.12.098. PMID 19217091.
- Donor Embryo: Online Guide for Potential Donors – RESOLVE: The National Infertility Association. Familybuilding.resolve.org. Retrieved on 3 August 2013.
- Beil, Laura (1 September 2009) "What happens to extra embryos after IVF?" CNN.
- Hug K (2008). "Motivation to donate or not donate surplus embryos for stem-cell research: Literature review". Fertility and Sterility 89 (2): 263–277. doi:10.1016/j.fertnstert.2007.09.017. PMID 18166188.
- "1978: First 'test tube baby' born". BBC. 25 July 1978. Retrieved 13 June 2009.
The birth of the world's first "test tube baby" has been announced in Manchester (England). Louise Brown was born shortly before midnight in Oldham and District General Hospital
- Moreton, Cole (14 January 2007). "World's first test-tube baby Louise Brown has a child of her own". The Independent (London). Retrieved 5 May 2010.
The 28-year-old, whose pioneering conception by in-vitro fertilisation made her famous around the world.. The fertility specialists Patrick Steptoe and Bob Edwards became the first to successfully carry out IVF by extracting an egg, impregnating it with sperm and planting the resulting embryo back into the mother
- Schulman, Joseph D. (2010) Robert G. Edwards – A Personal Viewpoint, CreateSpace Independent Publishing Platform, ISBN 1456320750.
- Is an "Indian Crab Syndrome" Impeding Indian Science? sciencemag.org. Retrieved 20 August 2013
- Ayers C (2004). "Mother wins $1m for IVF mix-up but may lose son". Timesonline.
- Swedberg, Claire (15 October 2007). "Reproductive Clinic Uses RFID to Guarantee Parental Identity". RFID Journal.
- Lawson, Dominic (11 March 2008). "Of course a deaf couple want a deaf child". The Independent (London). Retrieved Nov 12, 2009.
- Appel, Jacob (12 March 2009). More 'designer' options. The Winnipeg Sun
- Jha, Alok (31 May 2007). "Winston: IVF clinics corrupt and greedy". The Guardian (London).
- Dumit, J. (2012) Drugs for Life: How Pharmaceutical Companies Define Our Health. Duke University Press: Durham
- Dietrich, H (1986, May). "IVF: what can we do?" Paper presented to the Liberation or Loss? conference, Canberra.
- Warren MA (1988). "IVF and women's interests: an analysis of feminist concerns". Bioethics 2 (1): 37–57. doi:10.1111/j.1467-8519.1988.tb00034.x. PMID 11649236.
- "Is In Vitro Fertilization Being Overused?". CBS News. 2009-08-12.
- Parks JA (1996). "A closer look at reproductive technology and postmenopausal motherhood". CMAJ 154 (8): 1189–91. PMC 1487687. PMID 8612255.
- The Ethics Committee of the American Society for Reproductive Medicine (2009). "Access to fertility treatment by gays, lesbians, and unmarried persons". Fertil. Steril. 92 (4): 1190–3. doi:10.1016/j.fertnstert.2009.07.977. PMID 19732884.
- Appel JM (2006). "May doctors refuse infertility treatments to gay patients?". Hastings Cent Rep 36 (4): 20–1. doi:10.1353/hcr.2006.0053. PMID 16898357.
- Dolan, M. (29 May 2008) "State high court may give gays another victory". Los Angeles Times.
- Goldstein, Jacob (19 August 2008) California Doctors Can’t Refuse Care to Gays on Religious Grounds. Wall Street Journal.
- Egelko, Bob (19 August 2008), "Bob Doctors can't use bias to deny gays treatment", San Francisco Chronicle.
- Mohajer, Shaya Tayefe (25 October 2010). "License hearing for Octomom doctor resumes in LA". Associated Press.
- Breuer, Howard (22 October 2010). "Octomom's Doctor Tearfully Apologizes, Admits Mistake". People. Retrieved 22 May 2012.
- "Michael Kamrava’s medical license revoked". Los Angeles Times. 1 June 2011.
- Rafferty, Alessandra (25 February 2012). "Donor-Conceived and Out of the Closet". Newsweek.
- "‘My Daddy's Name is Donor’". NPR. 16 August 2010.
- Scheller, Christine A. "The Untold Story of Donor-Conceived Children". Christianity Today.
- Motluk, Alison (27 May 2011). "Canadian court bans anonymous sperm and egg donation". Nature. doi:10.1038/news.2011.329.
- "Donor-conceived children use Internet to find relatives and share information". Washington Post. 26 September 2011.
- McManus, Mike (24 June 2012). "Anonymous Father's Day". Greenfield Daily Reporter.
- Pro-Life Concerns About IVF Include Abortion, Exploitation. LifeNews.com (6 September 2011). Retrieved on 2013-08-03.
- "Pope Benedict XVI Declares Embryos Developed For In Vitro Fertilization Have Right To Life", Medical news today.
- Pope Paul VI (25 July 1968). "Humanae Vitae: Encyclical of Pope Paul VI on the Regulation of Birth, sec 12". Rome: Vatican. Retrieved 25 November 2008.
- Reconciling religion and infertility By Alina Dain. July 30, 2009
- "Catechism of the Catholic Church. Section 2377". Rome: Vatican. 1993. Retrieved 25 November 2008.
- Inhorn, MC (December 2006). "Making Muslim babies: IVF and gamete donation in Sunni versus Shi'a Islam". Cult Med Psychiatry 30 (4). pp. 427–50. doi:10.1007/s11013-006-9027-x. PMC 1705533. PMID 17051430.
- Tzitz Eliezer 9 p. 247
- Drah B. "Orphans in Sub-Saharan Africa: The Crisis, the Interventions, and the Anthropologist". Africa Today 59 (2 (Winter2012 2012)): 3–21. doi:10.2979/africatoday.59.2.3.
- Ilioi, E. C.; Golombok, S. (2014). "Psychological adjustment in adolescents conceived by assisted reproduction techniques: a systematic review". Human Reproduction Update 21 (1): 84–96. doi:10.1093/humupd/dmu051. ISSN 1355-4786.
- Throsby, K, Gill, R 2004, ‘"it’s different for men": masculinity and IVF’, LSE Research Online, Men and Masculinities, vol. 6, no. 4, pp. 340.
- Whittaker A 2009, ‘Global technologies and transnational reproduction in Thailand’, Asian Studies Review, vol. 33, no. 3, pp. 324
- Throsby, K, Gill, R 2004, ‘"it’s different for men": masculinity and IVF’, LSE Research Online, Men and Masculinities, vol. 6, no. 4, pp. 344
- Throsby, K, Gill, R 2004, ‘"it’s different for men": masculinity and IVF’, LSE Research Online, Men and Masculinities, vol. 6, no. 4, pp. 336
- Beutel M, Kupfer J, Kirchmeyer P, Kehde S, Köhn FM, Schroeder-Printzen I, Gips H, Herrero HJ, Weidner W (1999). "Treatment-related stresses and depression in couples undergoing assisted reproductive treatment by IVF or ICSI". Andrologia 31 (1): 27–35. doi:10.1111/j.1439-0272.1999.tb02839.x. PMID 9949886.
- Hammoud AO, Gibson M, Stanford J, White G, Carrell DT, Peterson M (2009). "In vitro fertilization availability and utilization in the United States: a study of demographic, social, and economic factors". Fertility and Sterility 91 (5): 1630–1635. doi:10.1016/j.fertnstert.2007.10.038. PMID 18539275.
- Kraft, Dina (17 July 2011) "Where Families Are Prized, Help Is Free", The New York Times
- Chambers GM, Sullivan EA, Ishihara O, Chapman MG, Adamson GD (June 2009). "The economic impact of assisted reproductive technology: a review of selected developed countries". Fertil. Steril. 91 (6): 2281–94. doi:10.1016/j.fertnstert.2009.04.029. PMID 19481642.
- Call for infertility care awareness. RTÉ News. 23 September 2009.
- Appel, J.M. (15 July 2009) Motherhood: Is It Ever Too Late? New York Times
- "More IVF babies but less multiple births". The Australian. 24 September 2009
- Gallagher, James. (8 July 2013) BBC News – IVF as cheap as £170, doctors claim. Bbc.co.uk. Retrieved on 2013-08-03.
- "China Bars In-Vitro Fertilization for Pregnancy". Redorbit.com. 12 November 2003. Retrieved 22 May 2012.
- Inhorn, Marcia C. "Islam, IVF and Everyday Life in the Middle East". AIME: Anthropology of the Middle East 1 (1): 37–45.
- "IVF Prohibition In Costa Rica". Ivfcostworldwide.com. Retrieved 22 May 2012.
- Murillo, Álvaro (12 July 2011) La Costa Rica católica se atasca con la fertilización in vitro. El Pais.
- CIDH Extends Deadline For Approval Of Law For In-Vitro Fertilization In Costa Rica. insidecostarica.com. 24 February 2011.
- Court strikes down Costa Rican ban on in-vitro fertilization. Associated Press via New York Times (22 December 2012)
- Australian court OKs fertility treatment for single women, lesbians by Peter O'Connor (AP, 18 April 2002)
- Hoare, Daniel (15 December 2007) Lesbian community welcomes Vic IVF changes. abc.net.au
- "21 CFR 1271.90(a)(2)". US Food and Drug Administration.
- "Fiscal Note, HB 2159 – SB 2136, from Tennessee General Assembly Fiscal Review Committee" (PDF). Retrieved 22 May 2012.
- "SB 0078 by Stanley, Bunch. (HB 0605 by DeBerry J, Hensley.)". Wapp.capitol.tn.gov. Retrieved 22 May 2012.
- "Tennessee Seeking To Ban IVF For Unmarried Individuals". Eggdonor.com. 31 March 2009. Retrieved 22 May 2012.
- Jones, Sam (1 November 2008). "Study shows barriers to same-sex adoption hurt children". Outandaboutnewspaper.com.
- "Legislative Update". Tnep.org. Retrieved 22 May 2012.
- Henig, Robin Marantz (2004). Pandora's Baby: How the First Test Tube Babies Sparked the Reproductive Revolution. New York: Houghton Mifflin. ISBN 0-618-22415-7.
- Hope T, Lockwood G, Lockwood M, Bewley S, Jackson J, Craft I (1995). "Should older women be offered in vitro fertilisation?". BMI 310 (6992): 1455–6. doi:10.1136/bmj.310.6992.1455. PMC 2549820. PMID 7613283.
- Seng SW, Yeong CT, Loh SF, Sadhana N, Loh SK (March 2005). "In-vitro fertilisation in women aged 40 years and above" (PDF). Singapore Med J 46 (3): 132–6. PMID 15735878.
- UK IVF clinics and statistics (HFEA)
- US information, statistics, and lists on assisted reproductive technology (CDC)